1. Field of the Invention
The present invention relates in general to a flexible touch-sense switch, and more specifically, to a redundant flexible touch-sense switch that is cooperatively activated by a deflection of a piezo-electric composite and a potential variation of an electromagnetic field.
2. Description of the Related Art
Vehicle input control devices typically require rotating a control knob, depressing a control button, or sliding a mechanical or electro-mechanical control switch to operate and activate a vehicle accessory device. Aside from typical pushbutton make and break switches, piezo-electric elements have been used for user interfaces such as keyboards, touch pads, switches, and the like. Piezoelectric elements exhibit a dielectric change when a mechanical distortion (pressure, stretch, or compression) is exerted on the piezoelectric element. The piezoelectric element may generate electrical charges when mechanically distorted. The distortion is typically the result from direct pressure or vibration exerted on the piezoelectric element. However, a drawback with using the piezoelectric element for vehicle switch actuation is that vibrations from the vehicle or road surfaces (e.g., bumps) may result in an unintended switch actuation.
Capacitive sensors have also been used for switch actuation. A capacitive sensor disposed under a surface fascia creates an electric field above the surface fascia. If an object is displaced within the electric field, a change of capacitance may be sensed to indicate a request by an operator to actuate a switch. Because the capacitive sensors are typically mounted under the surface of the fascia unit, activation of a switch may occur when an object is inadvertently placed on or in close proximity to the sensor. This ultimately can lead to activation of a device that was not intended. Furthermore, if the capacitive sensors are placed in close proximity to one another, overlapping electrical fields may occur which may also lead to activation of a switch adjacent to the switch intended for activation.